‘ Scientists uncover startling concentrations of pure DDT along seafloor off L.A. coast ‘

[btfc]

https://news.yahoo.com/scientists-uncove...17576.html

[mrbigstuff]

That's just beyond f'ed up. Hard to imagine a remediation solution that isn't unbelievably expensive.

[N-OS X-tasy!]

Reporting from the local rag: https://www.latimes.com/environment/stor...-l-a-coast

[Filliam H. Muffman]

It sounds like the question they have to answer is, how much DDT does it take to poison all the seas on the planet?

[Thrift Store Scott]

Filliam H. Muffman wrote:
It sounds like the question they have to answer is, how much DDT does it take to poison all the seas on the planet?

Since it has remained more or less concentrated in certain areas, I'm wondering if it is by nature more dense than seawater. That it hasn't dissipated into the surrounding seawater in all this time seems to suggest that when left undisturbed it doesn't mix easily with water, either. That could make cleanup somewhat easier, but vacuuming anything off the sea floor 3000 feet down isn't going to be a walk in the park regardless.

[gadje]

"Dumpsite Two."

Where is Dumpsite One?

[DeusxMac]

See Great Barrier Reef


"According to a study published in October 2012 by the Proceedings of the National Academy of Sciences, the reef has lost more than half its coral cover since 1985, a finding reaffirmed by a 2020 study which found over half of the reef's coral cover to have been lost between 1995 and 2017, with the effects of a widespread 2020 bleaching event not yet quantified."

"Another key threat faced by the Great Barrier Reef is pollution and declining water quality. The rivers of north-eastern Australia pollute the Reef during tropical flood events. Over 90% of this pollution comes from farm runoff. 80% of the land adjacent to the Great Barrier Reef is used for farming including intensive cropping of sugar cane, and major beef cattle grazing. Farming practices damage the reef due to overgrazing, increased run-off of agricultural sediments, nutrients and chemicals including fertilisers, herbicides and pesticides representing a major health risk for the coral and biodiversity of the reefs"

[JoeH]

Thrift Store Scott wrote:
[quote=Filliam H. Muffman]
It sounds like the question they have to answer is, how much DDT does it take to poison all the seas on the planet?

Since it has remained more or less concentrated in certain areas, I'm wondering if it is by nature more dense than seawater. That it hasn't dissipated into the surrounding seawater in all this time seems to suggest that when left undisturbed it doesn't mix easily with water, either. That could make cleanup somewhat easier, but vacuuming anything off the sea floor 3000 feet down isn't going to be a walk in the park regardless.
DDT is hydrophobic, almost completely insoluble in water. Its specific gravity is .99, or just barely less dense than the water. But due to its hydrophobic properties it tends to bind to organic material and soil particles. It degrades to other materials very slowly, there is an estimated half-life in aquatic environments of 150 years. The cold water at the depths it is located at will probably extend that. That DDT is going to be there for a long time. Fortunately because it doesn't dissolve well, the main methods that will cause spreading will be currents strong enough to move silt it is present in or other ocean bottom disturbances.

[RgrF]

other ocean bottom disturbances would presumably mean any attempts to siphon, dredge or otherwise remove the contaminant.

[JoeH]

RgrF wrote:
other ocean bottom disturbances would presumably mean any attempts to siphon, dredge or otherwise remove the contaminant.

Yep! Any attempt to remove the contaminated sediment would have to take that into account and take measures to minimize further spreading.

I am reminded of the arguments GE made against cleanup of the PCBs they contaminated both the Hudson and Housatonic RIvers from their manufacturing operations in the region. They argued with the EPA that the riverbed locations contaminated with PCBs should be left alone, the PCBs would remain in the sediment. The counterargument that finally was followed was that Spring floods and other changes in water flow would disturb the sediments anyways, so better to remove as much as feasible. Environmentally PCBs are not as persistent as DDT, so breakdown of the remaining PCB contamination will take much less time.